1. Field of the Invention
The present invention relates to a laser beam printer. More particularly, the present invention relates to a device for connecting an optional tray of a laser beam printer simultaneously with the placement thereof.
2. Discussion of Related Art
Typically, a laser beam printer converts an electric signal applied from a computer body, records it onto a paper. The laser beam printer scans the laser beam to a photosensitive drum to generate photo-current, thus performing a printing. Often, such a printer has a paper tray holding a limited number sheets of paper, causing the inconvenience of the need for frequent supply of papers. To solve this problem, development has been made on the auxiliary cassette with a large paper holding space. On this matter, exemplars of the contemporary practice include Wirthet al. (U.S. Pat. No. 5,593,152, Sheet Media Supply Tray Orients Sheets To Registration Posts In Imaging Apparatus, Jan. 14, 1997) discussing a sheet supply tray having a width alignment rail and a registration member against which the side of a received stack of sheets abuts when the stack is fully received in the imaging apparatus. Takagi et al. (U.S. Pat. No. 5,294,106, Image Forming Apparatus Having Detachable Sheet Cassette, Mar. 15, 1994) discussing an image forming apparatus in which probability of sheet jamming is reduced and jammed sheet can be easily removed. Penson (U.S. Pat. No. 4,830,354, Sheet Feed Apparatus And Cartridge Therefor, May 16, 1989) discusses a top-sheet feeding apparatus having an automatically elevating stack support tray to keep the top sheet of the stack in operative contact with sheet feed mechanism. Toriumi et al. (U.S. Pat. No. 4,621,272, Photosensitive Medium Cassette-Receiver System, Nov. 4, 1986) discusses an arrangement for detachably receiving a cassette containing photosensitive film sheets, which is includes a drive device for driving a light shielding cover of the cassette. Based on my study of these examples of the contemporary practice and the art, I find that there is a need for an improved and effective device for connecting an optional tray of a laser beam printer simultaneously with the placement thereof, which can automatically connect a connecting unit of the optional tray to a connecting unit of a printer body simultaneously with the placement of the printer body on the optional tray.